Democrats pulled off a shocking upset to win a rural Wisconsin state Senate seat Tuesday night, triggering alarm bells for Republicans across the state and nation.

Democrat Patty Schachtner defeated a well-known local Republican in a district that President Trump had carried by a whopping 55 percent to 38 percent just over a year ago.

Wisconsin Republicans sounded the alarm about what the results could mean, including that Gov. Scott Walker (R), who faces reelection next fall, suddenly looks considerably more vulnerable than he did one day ago.

Senate District 10 special election win by a Democrat is a wake up call for Republicans in Wisconsin.

This special election is the latest sign that Democrats are poised to have a huge 2018 midterm election — and one of the first concrete examples that they’re well-positioned not just in suburban territory but in rural areas as well. That’s crucial, as many of the U.S. senators they’re defending this year represent heavily blue collar, populist states like Missouri, West Virginia (and Wisconsin), and if they’re going to win back the House they need to pick up at least some GOP-leaning seats in more rural areas.

The district where Democrats triumphed last night covers the western sliver of Wisconsin’s Northwoods, encompassing some Minneapolis exurbs as well as a good swath of rural territory. Trump won it big after Romney carried it by a six-point margin in 2012, and it’s long been one of Republicans’ best-performing parts of the state. No Democrat has held this state senate seat in nearly two decades.

But Schachtner won by a nine-point margin despite the district’s strong GOP lean and her allies being outspent by GOP outside groups by a comfortable margin.

It’s not the first Democratic pickup in rural territory in the last 12 months, and they’ve shown big gains in other more rural, populist areas. But this result is scaring Republicans — and it should.

“The greater takeaway from the Wisconsin SD-10 special election is an alarm klaxon for Republicans at every level of the ballot, even those running in gerrymandered districts and drastically outspending their Democratic challengers,” Daily Kos Political Editor Carolyn Fiddler, an expert in state legislative elections, said in a statement. “The reckoning has arrived, and no one is safe.”